201117425 六、發明說明： 【發明所屬技術領域】 本發明關於三族氮化物半導體發光裝置，特別是關於 具有電流分散（current spreading)作用的電極結構之三 族氮化物半導體發光裝置。 在此，三族氮化物半導體發光裝置表示一種藉由電子 和電洞再結合（recombination)而產生光的三族II化物半 導體發光裝置。三族氮化物半導體由含有 Al(x)Ga(y)In(l-x-y)N(0^x^ 1 5 O^y^l » O^x+y^l) 的化合物所形成。此外，三族氮化物半導體發光裝置可表 示如：用於發紅色光的GaAs-基底三族氮化物半導體發光 裝置等。 【先前技術】 本節提供之本發明相關背景資訊不當然是習知技術。 第1圖為習知之三族氮化物半導體發光裝置的例子之 視圖。三族氮化物半導體發光裝置包括：基板10、形成於 基板10上的緩衝層20、形成於緩衝層20上的η型三族氮 化物半導體層30、形成於η型三族氮化物半導體層30上 的活性層40、形成於活性層40上的ρ型三族氮化物半導 體層50、形成於ρ型三族氮化物半導體層50上的ρ側電 極60、形成於ρ側電極60上的ρ側接合塾70、形成於藉 由台面刻钱（mesa-etching)p型三族氮化物半導體層50及 活性層40而露出之η型三族氮化物半導體層30上的η側 電極80、及保護膜90。 3 94936 201117425 關於基板10，可使用GaN基底基板作為同質基板 (homo-substrate)，且可使用藍寶石基板、SiC基板或Si 基板作為異質基板（hetero-substrate)。然而，可使甩任 何一種三族氮化物半導體層能成長於其上的基板。若使用 SiC基板’則η侧電極80可形成於SiC基板侧。 通常是藉由金屬有機化學蒸鍍法（M0CVD)的方式將三 族氮化物半導體層形成於基板10上。 緩衝層20係為了克服異質基板1〇和三族氮化物半導 體之間晶格常數及熱膨脹係數的差異。在第5, 122, 845號 美國專利中描述一種在38(TC至80(TC下，於藍寶石基板上 形成厚度為100 A至500 A的A1N緩衝層的技術，在第 5, 290, 393號美國專利中描述一種在200°C至900°C下，於 藍寶石基板上形成厚度為10 A至5000 A的 Al(x)Ga(l-x)N(0Sx<l)緩衝層之技術，以及在美國專利 公開案第2006/154454號中描述一種在600°C至990¾下形 成SiC緩衝層（晶種層），並在其上形成 <χ$1)層的技術。在形成η型三族氮化物半導體層30之 前’應先形成無摻雜（undoped)的GaN層為佳。可將其視為 緩衝層20或η型三族氮化物半導體層30的一部份。 關於η型氮化物半導體層30，在至少有η側電極80 形成於其中的區域（η型接觸層）摻入摻雜物。η型接觸層應 由摻雜有Si的GaN形成較佳。在美國專利第5, 733, 796 號中描述一種在目標摻雜濃度下，藉由調整Si和其他來源 材料的混合比例，以摻雜n型接觸層的技術。 4 94936 201117425 藉由電子和電洞再結合而產生光量子（light quanta) 的活性層40,最常由In(x)Ga(l-x)N(0<x$l)所製成’且 由單一量子井（quantum we 11)層或多重量子井層所構成。 p型三族氮化物半導體層50摻入適當的摻雜物例如： 鎮，藉由活化程序（activation process)提供p型導電性 (conductivity)。在第5, 247, 533號美國專利中描述一種 藉由電子束照射而活化p型三族氮化物半導體的技術，美 國專利第5, 306, 662號描述一種藉由以超過400°C之退火 (annealing)，活化p型三族氮化物半導體層的技術，並且 在美國專利公開案第2006/157714號中描述一種在無活化 程序下形成具有p型導電性的p型氮化物半導體層的技 術’藉由使用氨（ammonia)及聯胺基底（hydrazine-based) 來源材料作為氮前驅物，以形成P型氮化物半導體層。 提供p側電極60使電流平順地供給至整個P型三族氮 化物半導體層50。第5, 563, 422號美國專利中描述一種技 術有關形成幾乎覆蓋整個p型三族氮化物半導體層50的表 面’並與其歐姆接觸（ohmic contact)之由Ni和Au所製成 的透光性電極’且在第6, 515, 306號美國專利中描述一種 在p型三族氮化物半導體層上形成η型超晶格 (superlattice)層，並在其上形成由氧化銦錫（ΙΤ〇)所製成 之透光性電極的技術。 同時’可形成夠厚的ρ側電極60，使光不會通過而是 朝基板10反射。此技術稱為覆晶（flip chip)技術。在第 6’ 194’ 743號美國專利中描述一種有關電極結構之技術， 5 94936 201117425 該結構包括具有厚度超過2〇nm的Ag層、覆蓋Ag層的擴散 障壁（diffusion barrier)層、及覆蓋擴散障壁層且由Au 及A1所製成的連接（bonding)層。 提供p侧接合墊70及η側電極80用以供應電流及外 部導線連接（external wire- bonding)。在第 5, 563, 422 號美國專利中描述一種使用Ti及A1形成η側電極的技術。 保護膜90由Si〇2製成且為可省略的。 同時，η型三族氮化物半導體層30或p型三族氮化物 半導體層50可由單層或是多層所構成。近來，引進一種製 造垂直型發光裝置的技術，係藉由雷射蝕刻或是濕式姓刻 將基板10從三族氮化物半導體層上分離。 第2圖為美國專利第5, 563, 422號中一個電極結構實 例之視圖，其描述一種藉由在發光裝置相對之對角、線角落 的部分配置ρ側接合墊70和η側電極80，以改善電流分 佈的技術。 第3圖為美國專利第6, 307,218號中一個電極_構實 例之視圖，其描述一種藉由在ρ側接合墊71.知 11和η側電極 81之間以規律的間隔提供分支電極91，因著發光^置傾向 具有大面積，以改善電流分佈的技術。 然而，具上述電極結構的發光裝置有電流可能^集中在 靠近P側接合墊71或11側電極81之區域{^的問#。 【發明内容】 (發明欲解決之課題） 在稍後本發明的較佳實施態樣中，描述藉由本發明解 94936 6 201117425 決該等問題。 (解決課題之方法） 本節提供本發明一般性概要，但並非包括本發明全部 的範圍或全部的特徵。 根據本發明的一個實施態樣，其係提供一種藉由電子 和電洞再結合而產生光的三族氮化物半導體發光裝置，此 三族氮化物半導體發光裝置包括：供應電流使電子和電洞 再結合的第一電極和第二電極；延伸自第一電極的第一分 支電極；及延伸自第二電極的第二分支電極，至少一部份 的第二分支電極的厚度與第一分支電極的厚度相異。 (發明之功效） 將在稍後本發明的較佳實施態樣中，描述本發明之功 效。 【實施方式】 藉由參考所附圖示詳細說明本發明。 在下列本發明的說明中，將會省略與習知技術類似或 相同的重複敘述。 第4圖為本發明三族氮化物半導體發光裝置所提供之 電極結構之一實例的視圖。本發明之三族氮化物半導體發 光裝置中的電極結構包括：電極110和120，以及各自延 伸出的分支電極113和123。 電極110和120包括：與三族氮化物半導體發光裝置 中η型三族氮化物半導體層或p型三族氮化物半導體層其 中一者電性連接的第一電極110,以及與另一者電性連接 7 94936 201117425 的第二電極120。 在此實例中，第一電極110和第二電極12〇各可提供 作為P側接合墊或η側接合墊。 由下將可知分支電極113和123各可提供為單一分支 電極。在此’於下列的敘述中，則將假設提供複數個分支 電極 113a、113b、113c、123a 及 123b。 亦即分支電極113和123包括：複數個延伸自第一電 極的113的第一分支電極113a、U3b及n3c，及複數個 延伸自第二電極的第二分支電極12如及123b。 此外，在此實例中，提供至少兩個彼此厚度相異的分 支電極113和123。 其目的欲使流經各分支電極113和123的電流強度相 異。 因此，可防止電流在第一電極11〇和第二電極12〇之 間不均勻地分散而集中在某些區域的現象，如：電流分佈 變得不均勻的問題。 接著更詳細地加以描述。 “在此實例中，第一電極110和第二電極120提供於發 光裝置的外面部分並圍繞著發光裝置的中央部份形成對 稱。 在延伸自第一電極110的第一分支電極113a、113b、 113c备中，第一分支電極113a配置在第一區域，第一 分支電極11.3b配置在第二區域以，第-分支電極⑽配 置在第三區域R3。 94936 8 201117425 在K申自第一電極120的第二分支電極123a、123b 當中’第二分支電極123a配置在第一分支電極㈣和第 一 /刀支電極113b之間，第二分支電極12北配置在地第一 分支電極113b和第一分支電極113c之間。 既然如此，考量到第一電極11〇和第二電極的配置， 其及刀支電極112和113的配置，相較於第二區域R2和第 三區域R3’電流較集中於位在連接第一電極11〇和第二電 極120之假想直線上的第一區域R1，而第二區域r2則較 第三區域R3更為集中。 為了預防上述的問題，在此實例中，第二分支電極 123a厚度T2設定成大於第一分支電極U3a的厚度π，且 第一分支電極113b的厚度T3設定成大於第二分支電極 123a的厚度T2。 此外，分支電極距離發光裝置中央越遠，其厚度越厚。 換言之，第4圖中分支電極的厚度滿足‘Τ1<Τ2<Τ3<Τ4 <T5’ 。 因此，流過配置在電流相對少的區域之分支電極的電 流強度，相較於流過配置在電流相對集中的區域之分支電 極的電流強度變得較強，能減緩或預防電流的集中。 同時，在此實例中，由於在第一分支電極113a、U3b 和113c及在第二分支電極123a和123b之間產生電流流 動，第一分支電極113a、113b和113c及在第二分支電極 123a和123b在發光裝置中央朝外的方向上，應一個接一 個交錯地排列，因此電流密度能更均勻的分佈。 94936 9 201117425 此外，在此實例中，由於第一電極110和第二電極120 位在連接第一電極110和第二電極120的假想直線可通過 發光裝置中央的位置上，圍繞著假想直線配置成對稱的第 一分支電極113a、113b和113c及第二分支電極123a和 123b可具有相同的厚度。因此，在設計第一和第二分支電 極的厚度時可變得較為簡單。 再者，在此實例中，第一電極110和第二電極120的 形狀並不限於第4圖中的圓形，可為橢圓、多邊形等。 在此實例中，分支電極的厚度ΤΙ、T2和T3為藉由發 光裝置的尺寸和形狀、分支電極的分佈外形、電極的位置 和形狀的試驗所取決之數值。 換言之，藉由流經電流強度增加的區域之試驗來減少 分支電極的厚度可達成本發明的目的。 同時，在此實例中，分支電極之間的間距可設成規律 的。然而，具有相對高電流密度的第一區域R1之間距設定 成大於具有相對低電流密度的第二區域R2之間距為佳。 第5圖為本發明三族氮化物半導體發光裝置提供之電 極結構之另一實例的視圖。當本實例之電極結構相似於上 之電極結構時，兩者之差異在於第一電極210和第二電 極220中至少一者為兩個或更多個相互連接的多迴路電極 (split elect rode )211和212，並供應分離的電流。 供應電流的接合導線偶合各多迴路電極211和212。 因此，供應流過一接合導線之的電流係分別供應流過 複數個接合導線，因此可穩定其供應。 10 94936 201117425 特別是，由於在發光裝置此範圍的增加造成驅動發光 裝置的電流強度增加。既然如此，多迴路電極即有效用。 . 此外，在此實例中，關於分支電極213和223的厚度， . 以和上述相同的原則，配置在具有相對高電流密度區域的 分支電極之厚度，設定咸小於配置在具有相對低電流密度 區域的分支電極之厚度。 又，第一電極210和第二電極220以位在連接第一電 極210和第二電極220之假想直線能通過發光裝置中央的 位置上為佳。 第6圖為本發明三族氮化物半導體發光裝置的電極結 構之又一實例的視圖。當根據本實例的電極結構相似於上 述之電極結構時’兩者之差異在於第一電極310和第二電 極320中至少一者為兩個或更多個彼此分開的多迴路電極 311及312 ’並供應分離的電流。 如同稍早之討論’由於在發光裝置此範圍的增加造成 驅動發光裝置的電流強度增加。此驅動電流係分別地供應 以穩定電流供應。 此外’各多迴路電極311和312彼此分開以達到電流 欲度的均勻化.。 再者，在此實例中，關於分支電極313和323的厚度， 配置在具有相對高電流密度之區域的分支電極之厚度設定 成小於配置在具有相對低電流密度之區域的分支電極之厚 度。 第7圖為本發明三族氮化物半導體發光裝置所提供之 11 94936 201117425 電極結構之其他實例的視圖。當本實例之電極結構相似於 上述之電極結構時，兩者之差異在於第一分支電極、 413b和413c及第二分支電極423a和423b中至少一者為 在縱向有厚度改變。 考量到一分支電極在各別部分根據其位置具有不同的 電流密度，因此藉由各別部分具有不同的厚度，欲減緩或 防止電流密度的差異。 ' 亦即，在形成一分支電極的各別部分當中位在具有 相對高電流密度區域的部分之厚度設定成小於位在具 對低電流密度區域的部分之厚度。 八 =第8圖至第10圖’當;二分支電極的某些部分或 第一分支電極的某些部分圍繞第一電極41〇 $第二電極 =二Γ電極140和某些部分的第二分支電極42北之 和川第一電極和某些部分的第一分支電極413b -問間’會產生相對高電流密度。為了解決或減缓此 以、bi 一分支電極或第二分支電極中某些部分的厚度 :和以設定成小於其他部分的厚度—和… 將描述本發明的各種具體型態。 同厚^體發光裝置，包括複數個具有不 J刀叉電極。其可改善電流的集中。 縱向化物半導體發光裝置，包括具有厚度在 m—、刀一支電極。其可減缓或防止電流的集中。 數伽夕、—種三族氮化物半導體發光裝置，包括藉由連接游 夕题路電極所形成的電極，以便複數個接^導線連接 94936 12 201117425 於其上，連同具體實施型態和（2)。即使在任一多迴路 電極當中有導線連接故障，依然可改善電流的集中。 • (4)一種三族氮化物半導體發光裝置’包括藉由複數個 . 彼此分開的多迴路電極所形成的電極，連同具體實施型態 (1)和（2)。在大面積的發光裝置中可改善電流密度的均勻 性0 根據本發明的三族氮化物半導體發光裝置，使在不同 分支電極之間的電流密度均勻，如此使得發光裝置整體的 電流密度能均勻。 根據本發明的三族氮化物半導體發光裝置，使在圍繞 分支電極所產生之電流密度均勻，如此使得發光裝置整體 的電流密度能均勻。 根據本發明的三族氮化物半導體發光裝置，即使任一 多迴路電極導線連接故障，依然可改善電流的集中。 根據本發明的三族氮化物半導體發光裝置，可改善大 面積發光裝置中大驅動電流所引起之電流密度的不均。 【圖式簡單說明】 第1圖為習知三族氮化物半導體發光裝置實例之視圖。 第2圖為第5, 563, 422號美國專利中所描述之電極沾 構實例之視圖。 … 第3圖為第6,307, 218號美國專利中所描述之 結構實例之視圖。 第4圖為本發明三族氮化物半導體發光裝置所提供之 電極結構之一實例的視圖。 94936 13 201117425 第5圖為本發明三族氮化物半導體發光裝置所提供之 電極結構另〜實例的視圖。 第6圖為本發明三族氮化物半導體發光裝置所提供之 電極結構又〜實例的視圖。 第7圖為本發明三族氮化物半導體發光裝置所提供之 電極結構其他實例的視圖。 第8圖至第1〇圖為第7圖中A、B及C部分的放大視 圖。 【主要元件符號說明】 10 基板 20 緩衝層 30 η型三族氮化物半導體層 40 活性層 50 Ρ型三族氮化物半導體層 60 Ρ側電極 70、71 ρ侧接合墊 80、81 η側電極 90 保護膜 9卜 113、123、213、223、323、413、423 分支電極 110、210、310、410 第一電極 113a、113b、113c、213a、213b、213c、413a、413b、413c 第一分支電極 120、220、323a、323b、320、420 第二電極 123a、123b、223a、223b、423a、423b 第二分支電極 211、212、311、312、411、412 多迴路電極 A、B、C部分 R卜R2、R3 區域 Π、T2、T3、T4、T5、a卜 a2、b卜 b2、c卜 c2 厚度 14 94936BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a group III nitride semiconductor light-emitting device, and more particularly to a group III nitride semiconductor light-emitting device having an electrode structure having a current spreading action. Here, the Group III nitride semiconductor light-emitting device represents a Group III II semiconductor light-emitting device which generates light by electron and hole recombination. The Group III nitride semiconductor is formed of a compound containing Al(x)Ga(y)In(l-x-y)N(0^x^1 5 O^y^l » O^x+y^l). Further, the Group III nitride semiconductor light-emitting device can be expressed, for example, a GaAs-based Group III nitride semiconductor light-emitting device for emitting red light. [Prior Art] The background information related to the present invention provided in this section is not of course a conventional technique. Fig. 1 is a view showing an example of a conventional group III nitride semiconductor light-emitting device. The group III nitride semiconductor light-emitting device includes a substrate 10, a buffer layer 20 formed on the substrate 10, an n-type group III nitride semiconductor layer 30 formed on the buffer layer 20, and an n-type group III nitride semiconductor layer 30. The upper active layer 40, the p-type group III nitride semiconductor layer 50 formed on the active layer 40, the p-side electrode 60 formed on the p-type group III nitride semiconductor layer 50, and ρ formed on the p-side electrode 60 a side junction germanium 70, an n-side electrode 80 formed on the n-type group III nitride semiconductor layer 30 exposed by the mesa-etching of the p-type group III nitride semiconductor layer 50 and the active layer 40, and Protective film 90. 3 94936 201117425 Regarding the substrate 10, a GaN base substrate can be used as a homo-substrate, and a sapphire substrate, a SiC substrate, or a Si substrate can be used as a hetero-substrate. However, it is possible to grow a substrate on which any of the group III nitride semiconductor layers can be grown. When the SiC substrate ' is used, the n-side electrode 80 can be formed on the SiC substrate side. The group III nitride semiconductor layer is usually formed on the substrate 10 by metal organic chemical vapor deposition (M0CVD). The buffer layer 20 is for overcoming the difference in lattice constant and thermal expansion coefficient between the hetero-substrate 1 〇 and the group III nitride semiconductor. A technique for forming an A1N buffer layer having a thickness of 100 A to 500 A on a sapphire substrate at 38 (TC to 80 (TC, TC, No. 5, 290, 393) is described in U.S. Patent No. 5,122,845. U.S. Patent describes a technique for forming an Al(x)Ga(lx)N(0Sx<l) buffer layer having a thickness of 10 A to 5000 A on a sapphire substrate at 200 ° C to 900 ° C, and in the United States. A technique of forming a SiC buffer layer (seed layer) at 600 ° C to 9903⁄4 and forming a layer of <χ$1) thereon is described in Patent Publication No. 2006/154454. Forming a n-type group III nitride It is preferable that an undoped GaN layer is formed before the semiconductor layer 30. This may be regarded as a part of the buffer layer 20 or the n-type group III nitride semiconductor layer 30. About the n-type nitride semiconductor layer 30. A dopant is doped in a region (n-type contact layer) in which at least the n-side electrode 80 is formed. The n-type contact layer should be formed of GaN doped with Si. In U.S. Patent No. 5,733, No. 796 describes a technique for doping n-type contact layers by adjusting the mixing ratio of Si and other sources at a target doping concentration. 4 94936 201117425 The active layer 40 of light quanta is produced by recombination of electrons and holes, most often made of In(x)Ga(lx)N(0<x$l)' and consists of a single A quantum well layer or a multiple quantum well layer is formed. The p-type group III nitride semiconductor layer 50 is doped with a suitable dopant such as a town, and provides p-type conductivity by an activation process ( A technique for activating a p-type Group III nitride semiconductor by electron beam irradiation is described in U.S. Patent No. 5, 247, 533, the disclosure of which is incorporated herein by reference. Annealing of C, a technique for activating a p-type group III nitride semiconductor layer, and a method of forming a p-type nitride semiconductor having p-type conductivity without an activation process is described in US Patent Publication No. 2006/157714 The layer technique 'by using ammonia and a hydrazine-based source material as a nitrogen precursor to form a P-type nitride semiconductor layer. The p-side electrode 60 is provided to smoothly supply current to the entire P-type A group III nitride semiconductor layer 50. A technique for forming a translucent electrode made of Ni and Au which forms a surface almost covering the entire p-type group III nitride semiconductor layer 50 and is ohmic contact thereof is described in U.S. Patent No. 5,563,422. And forming an n-type superlattice layer on a p-type group III nitride semiconductor layer, and forming an indium tin oxide (yttrium) layer thereon, is described in U.S. Patent No. 6,515,306. A technique for making a translucent electrode. At the same time, a thick ρ-side electrode 60 can be formed so that light does not pass but is reflected toward the substrate 10. This technique is known as flip chip technology. A technique relating to electrode structures is described in U.S. Patent No. 6, 194, 743, the disclosure of which is incorporated herein by reference. A barrier layer and a bonding layer made of Au and A1. A p-side pad 70 and an n-side electrode 80 are provided for supplying current and external wire-bonding. A technique for forming an n-side electrode using Ti and A1 is described in U.S. Patent No. 5,563,422. The protective film 90 is made of Si〇2 and can be omitted. Meanwhile, the n-type group III nitride semiconductor layer 30 or the p-type group III nitride semiconductor layer 50 may be composed of a single layer or a plurality of layers. Recently, a technique for fabricating a vertical type light-emitting device has been introduced in which a substrate 10 is separated from a group III nitride semiconductor layer by laser etching or wet etching. Figure 2 is a view showing an example of an electrode structure in U.S. Patent No. 5,563,422, which describes the provision of a p-side pad 70 and an n-side electrode 80 in a portion opposite to the diagonal and line corners of the light-emitting device, A technique to improve current distribution. Fig. 3 is a view showing an example of an electrode configuration in the U.S. Patent No. 6,307,218, which is characterized in that a branch electrode 91 is provided at regular intervals between the p-side bonding pad 71 and the n-side electrode 81, A technique for improving the current distribution due to the tendency of the light to have a large area. However, the light-emitting device having the above-described electrode structure has a current which may be concentrated in a region close to the P-side bonding pad 71 or the 11-side electrode 81. SUMMARY OF THE INVENTION (Problems to be Solved by the Invention) In a preferred embodiment of the present invention, the problems are solved by the solution of the present invention 94936 6 201117425. (Means for Solving the Problem) This section provides a general summary of the present invention, but does not include all or all of the features of the present invention. According to an embodiment of the present invention, there is provided a Group III nitride semiconductor light-emitting device that generates light by recombining electrons and holes, the Group III nitride semiconductor light-emitting device comprising: supplying current to make electrons and holes a first electrode and a second electrode recombined; a first branch electrode extending from the first electrode; and a second branch electrode extending from the second electrode, a thickness of the at least one portion of the second branch electrode and the first branch electrode The thickness varies. (Effect of the Invention) The effects of the present invention will be described later in a preferred embodiment of the present invention. [Embodiment] The present invention will be described in detail by referring to the accompanying drawings. In the following description of the invention, repeated descriptions similar or identical to the prior art will be omitted. Fig. 4 is a view showing an example of an electrode structure provided by the Group III nitride semiconductor light-emitting device of the present invention. The electrode structure in the Group III nitride semiconductor light-emitting device of the present invention comprises electrodes 110 and 120, and branch electrodes 113 and 123 which are each extended. The electrodes 110 and 120 include: a first electrode 110 electrically connected to one of an n-type group III nitride semiconductor layer or a p-type group III nitride semiconductor layer in the group III nitride semiconductor light-emitting device, and the other electrode The second electrode 120 of 7 94936 201117425 is connected. In this example, the first electrode 110 and the second electrode 12'' each may be provided as a P-side bonding pad or an n-side bonding pad. As will be understood from the following, the branch electrodes 113 and 123 can each be provided as a single branch electrode. Here, in the following description, it is assumed that a plurality of branch electrodes 113a, 113b, 113c, 123a, and 123b are provided. That is, the branch electrodes 113 and 123 include a plurality of first branch electrodes 113a, U3b, and n3c extending from the first electrode 113, and a plurality of second branch electrodes 12 and 123b extending from the second electrode. Further, in this example, at least two branch electrodes 113 and 123 which are different in thickness from each other are provided. The purpose is to make the currents flowing through the branch electrodes 113 and 123 different in intensity. Therefore, it is possible to prevent a phenomenon in which current is unevenly dispersed between the first electrode 11A and the second electrode 12A and concentrated in certain regions, such as a problem in which the current distribution becomes uneven. This will be described in more detail. "In this example, the first electrode 110 and the second electrode 120 are provided to the outer portion of the light emitting device and are symmetric about the central portion of the light emitting device. The first branch electrodes 113a, 113b extending from the first electrode 110, In the 113c standby, the first branch electrode 113a is disposed in the first region, the first branch electrode 11.3b is disposed in the second region, and the first branch electrode (10) is disposed in the third region R3. 94936 8 201117425 The second branch electrodes 123a, 123b of 120 are disposed between the first branch electrode (four) and the first/knife electrode 113b, and the second branch electrode 12 is disposed at the ground first branch electrode 113b and Between a branch electrode 113c. In this case, the configuration of the first electrode 11A and the second electrode is considered, and the arrangement of the blade electrodes 112 and 113 is compared with the current of the second region R2 and the third region R3'. Focusing on the first region R1 on the imaginary straight line connecting the first electrode 11 〇 and the second electrode 120, and the second region r2 is more concentrated than the third region R3. To prevent the above problem, in this example ,second The thickness T2 of the branch electrode 123a is set larger than the thickness π of the first branch electrode U3a, and the thickness T3 of the first branch electrode 113b is set larger than the thickness T2 of the second branch electrode 123a. Further, the farther the branch electrode is from the center of the light-emitting device, In other words, the thickness of the branch electrode in Fig. 4 satisfies 'Τ1<Τ2<Τ3<Τ4 <T5'. Therefore, the current intensity of the branch electrode disposed in the region where the current is relatively small is compared with the flow The current intensity of the branch electrodes disposed in the region where the current is relatively concentrated becomes stronger, and the concentration of the current can be slowed down or prevented. Meanwhile, in this example, since the first branch electrodes 113a, U3b, and 113c and the second branch Current flows between the electrodes 123a and 123b, and the first branch electrodes 113a, 113b, and 113c and the second branch electrodes 123a and 123b are arranged alternately one after another in the direction in which the center of the light-emitting device faces outward, so that the current density can be More uniform distribution. 94936 9 201117425 Further, in this example, since the first electrode 110 and the second electrode 120 are connected to the first electrode 110 and the second electrode 1 The imaginary straight line of 20 may pass through the center of the light-emitting device, the first branch electrodes 113a, 113b, and 113c and the second branch electrodes 123a and 123b which are symmetrically arranged around the imaginary straight line may have the same thickness. Therefore, in the design first And the thickness of the second branch electrode can be made simpler. Further, in this example, the shapes of the first electrode 110 and the second electrode 120 are not limited to the circular shape in FIG. 4, and may be an ellipse, a polygon, or the like. In this example, the thicknesses T, T2, and T3 of the branch electrodes are values determined by tests of the size and shape of the light-emitting device, the distribution profile of the branch electrodes, and the position and shape of the electrodes. In other words, it is possible to reduce the thickness of the branch electrode by the test of the region where the current intensity is increased to achieve the object of the invention. Meanwhile, in this example, the spacing between the branch electrodes can be set to be regular. However, it is preferable that the distance between the first regions R1 having a relatively high current density is set to be larger than the distance between the second regions R2 having a relatively low current density. Fig. 5 is a view showing another example of the electrode structure provided by the Group III nitride semiconductor light-emitting device of the present invention. When the electrode structure of the present example is similar to the upper electrode structure, the difference is that at least one of the first electrode 210 and the second electrode 220 is two or more interconnected multi-circuit electrodes (split elect rods). 211 and 212, and supply separate currents. The bonding wires supplying the current couple the respective multi-circuit electrodes 211 and 212. Therefore, the current supplied through a bonding wire is supplied to flow through a plurality of bonding wires, respectively, so that the supply thereof can be stabilized. 10 94936 201117425 In particular, the current intensity of the driving light-emitting device is increased due to an increase in this range of the light-emitting device. In this case, the multi-circuit electrode is effective. Further, in this example, regarding the thicknesses of the branch electrodes 213 and 223, in the same principle as described above, the thickness of the branch electrode disposed in the region having a relatively high current density is set to be less than that in the region having a relatively low current density. The thickness of the branch electrodes. Further, it is preferable that the first electrode 210 and the second electrode 220 are located at a position where the imaginary straight line connecting the first electrode 210 and the second electrode 220 can pass through the center of the light-emitting device. Fig. 6 is a view showing still another example of the electrode structure of the Group III nitride semiconductor light-emitting device of the present invention. When the electrode structure according to the present example is similar to the electrode structure described above, the difference between the two is that at least one of the first electrode 310 and the second electrode 320 is two or more multi-circuit electrodes 311 and 312 separated from each other. And separate current is supplied. As discussed earlier, the current intensity of the driving light-emitting device is increased due to an increase in the range of the light-emitting device. This drive current is supplied separately to stabilize the current supply. Further, the respective multi-circuit electrodes 311 and 312 are separated from each other to achieve uniformization of current. Further, in this example, regarding the thickness of the branch electrodes 313 and 323, the thickness of the branch electrode disposed in the region having a relatively high current density is set to be smaller than the thickness of the branch electrode disposed in the region having a relatively low current density. Fig. 7 is a view showing another example of the electrode structure of 11 94936 201117425 provided by the group III nitride semiconductor light-emitting device of the present invention. When the electrode structure of the present example is similar to the electrode structure described above, the difference is that at least one of the first branch electrodes, 413b and 413c and the second branch electrodes 423a and 423b has a thickness change in the longitudinal direction. It is considered that a branch electrode has different current densities depending on its position in each part, and therefore, the respective portions have different thicknesses, and it is intended to slow or prevent the difference in current density. That is, the thickness of the portion located in the region having the relatively high current density among the respective portions forming a branch electrode is set to be smaller than the thickness of the portion located in the region having the low current density. Eight = Fig. 8 to Fig. 10 'When; some portions of the two branch electrodes or portions of the first branch electrode surround the first electrode 41 第二 $ second electrode = two electrodes 140 and some portions of the second The first electrode of the north electrode of the branch electrode 42 and the first branch electrode 413b of some portions may have a relatively high current density. In order to solve or alleviate the thickness of some portions of the bi-branch electrode or the second branch electrode: and to be set to be smaller than the thickness of other portions - and ... various specific forms of the invention will be described. The same thick body light emitting device includes a plurality of electrodes having a non-J knife. It improves the concentration of current. A longitudinally structured semiconductor light-emitting device comprising an electrode having a thickness of m-, a knife. It can slow or prevent the concentration of current. a gamma-gamma-based nitride semiconductor light-emitting device comprising an electrode formed by connecting electrodes of an epoch, so that a plurality of wires are connected to 94936 12 201117425, together with a specific implementation and (2) ). Even if there is a wire connection failure in any of the multi-circuit electrodes, the current concentration can be improved. (4) A Group III nitride semiconductor light-emitting device 'includes an electrode formed by a plurality of multi-circuit electrodes separated from each other, together with specific embodiments (1) and (2). The uniformity of current density can be improved in a large-area light-emitting device. According to the group III nitride semiconductor light-emitting device of the present invention, the current density between the different branch electrodes is made uniform, so that the current density of the entire light-emitting device can be made uniform. According to the Group III nitride semiconductor light-emitting device of the present invention, the current density generated around the branch electrodes is made uniform, so that the current density of the entire light-emitting device can be made uniform. According to the group III nitride semiconductor light-emitting device of the present invention, even if any of the multi-circuit electrode wire connection failures, the concentration of current can be improved. According to the Group III nitride semiconductor light-emitting device of the present invention, unevenness in current density caused by a large driving current in a large-area light-emitting device can be improved. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing an example of a conventional group III nitride semiconductor light-emitting device. Figure 2 is a view of an example of electrode deposition as described in U.S. Patent No. 5,563,422. Fig. 3 is a view showing an example of the structure described in U.S. Patent No. 6,307,218. Fig. 4 is a view showing an example of an electrode structure provided by the Group III nitride semiconductor light-emitting device of the present invention. 94936 13 201117425 Fig. 5 is a view showing another example of an electrode structure provided by the group III nitride semiconductor light-emitting device of the present invention. Fig. 6 is a view showing an electrode structure and an example provided by the group III nitride semiconductor light-emitting device of the present invention. Fig. 7 is a view showing another example of the electrode structure provided by the group III nitride semiconductor light-emitting device of the present invention. Fig. 8 to Fig. 1 are enlarged views of portions A, B and C of Fig. 7. [Main component symbol description] 10 substrate 20 buffer layer 30 n-type group III nitride semiconductor layer 40 active layer 50 germanium-type group III nitride semiconductor layer 60 germanium side electrode 70, 71 p-side bonding pad 80, 81 n-side electrode 90 Protective film 9 113, 123, 213, 223, 323, 413, 423 branch electrode 110, 210, 310, 410 first electrode 113a, 113b, 113c, 213a, 213b, 213c, 413a, 413b, 413c first branch electrode 120, 220, 323a, 323b, 320, 420 second electrodes 123a, 123b, 223a, 223b, 423a, 423b second branch electrodes 211, 212, 311, 312, 411, 412 multi-circuit electrodes A, B, C parts R卜R2, R3 region Π, T2, T3, T4, T5, ab a2, bb b2, cb c2 thickness 14 94936